1. Field of the Invention
The present invention relates generally to an apparatus for performing circular anastomosis of hollow tissue organs having a detachable anvil rod of improved structure. The invention is also directed to a detachable anvil rod having improved structure.
2. Description of the Prior Art
Anastomosis is the surgical joining of separate hollow organ sections so that the sections intercommunicate with each other. Typically, the anastomosis procedure follows surgery in which a diseased or defective section of hollow tissue is removed and the remaining end sections are to be joined. Depending on the desired anastomosis procedure, the end sections may be joined by either circular, end-to-side or side-to-side organ reconstruction methods.
In a circular anastomosis procedure, the two ends of the organ sections are joined by means of a stapling instrument which drives a circular array of staples through the end sections and simultaneously cores any overlapping tissue to free the tubular passage.
Examples of instruments for performing circular anastomosis of hollow organs are described in U.S. Pat. Nos. 4,304,236, 4,379,457, 4,573,468, 4,576,167, 4,603,693, 4,646,745 and 5,119,983. These instruments typically include an elongated shaft having a handle portion at a proximal end to actuate the instrument and a staple holding component disposed at a distal end. An anvil component including an anvil rod with attached anvil head is mounted to the distal end. Opposed end portions of the organs to be stapled are clamped between the anvil head and the staple holding component. The clamped tissue is stapled by driving one or more staples from the staple holding component so that the ends of the staples pass through the tissue and are clinched by the anvil head.
In some applications of the circular anastomosis procedure, the anvil rod with attached anvil head is mounted to the distal end of the shaft prior to insertion of the instrument into the tissue to be anastomised. However, in other applications, it is preferable to utilize a detachable anvil rod which may be mounted to the instrument subsequent to positioning of the instrument and the anvil component within their respective tissue sections. In such instances, the stapling instrument and the anvil component are separately applied to the operative site. Each tissue section is then secured to their respective anvil or staple holding component by a purse string. The anvil component is mounted to the surgical instrument by inserting a mounting portion of the anvil rod within the distal end of the instrument so that a mounting mechanism within the instrument securely engages the rod. Preferably, preparation of the tissue sections to be joined and mounting of the anvil rod to the instrument are performed using minimally invasive surgical techniques, i.e., under laparoscopic guidance.
FIG. 1 illustrates a detachable anvil rod 10 which is presently used with instruments of the type described and in the aforedescribed manner. This anvil rod is a component of the PREMIUM CEEA.TM. instrument which is manufactured by United States Surgical Corporation and is the subject of U.S. Pat. No. 5,119,983, the contents of which are incorporated herein by reference. The anvil rod includes a mounting portion 12 which has a pointed conical shape at the mounting end, which is inserted within the elongated shaft of the stapling instrument to engage the rod mounting mechanism within the shaft to effect the mounting. The central portion of the anvil rod includes external splines 14 for properly aligning the rod with the staple firing mechanism and an anvil head mounting portion 16 to house the anvil head. The anvil head mounting portion may also include external splines 18 which properly align the anvil head with the stapling firing mechanism to ensure proper reception of the ejected staples into the staple receiving buckets within the anvil head.
Although the detachable anvil rod illustrated in FIG. 1 has many advantages in its application, it would be advantageous to improve the mounting portion. For example, a mounting portion which is relatively narrowly configured may increase user flexibility and facilitate mounting of the rod, particularly when the surgery is performed under laparoscopic guidance, by increasing the range of angular positions at which the rod may be oriented and inserted within the distal end of the apparatus during mounting. Another possible improvement to the rod involves providing structure which will facilitate grasping of the rod with a grasping instrument (e.g., a laparoscopic instrument) so as to enhance maneuvering of the rod about the operative site where blood and other bodily fluids are present.
Accordingly, the present invention is directed to an anvil rod and related applications which has improved structure to facilitate mounting of the rod and maneuvering of the rod about the operative site. The improved structure also facilitates use of the rod during endoscopic or laparoscopic procedures.